JP6455099B2 - Solar cell unit and method for manufacturing solar cell unit - Google Patents

Description

  The present invention relates to a solar cell unit and a method for manufacturing a solar cell unit.

  In the solar cell unit, the bus bar electrode and the wiring member (tab wire) electrically connected to the surface electrode (thin wire electrode) etc. of one solar cell are electrically connected to the bus bar electrode etc. on the back surface of the other solar cell. The connection is sequentially repeated, and a plurality of solar cells are connected in series and / or in parallel. Since solar cells are used in outdoor environments, it is necessary to ensure resistance to temperature changes, moisture, strong winds, snow accumulation, etc., and the solar cell group to which the bus bar electrodes and wiring members are connected is sealed with a sealing member. It is common. Usually, a plurality of sealing members such as ethylene vinyl acetate (EVA) are sandwiched between tempered glass and a back sheet, and further sandwiched between the sealing members so as to laminate a group of solar cells to which wiring members are connected. Thereafter, sealing is performed by a vacuum laminator.

  Conventionally, solder has been used for joining an electrode and a wiring member when producing a solar cell unit (see, for example, Patent Documents 1 and 2 below). Solder is widely used because it is excellent in connection reliability such as electrical conductivity and fixing strength, is inexpensive and versatile. However, in the soldering method, since the melting temperature of the solder is usually about 230 to 260 ° C., the high temperature accompanying the joining, the volumetric shrinkage of the solder, etc. adversely affect the semiconductor structure of the solar battery cell. It may cause characteristic deterioration.

  On the other hand, a joining method using an adhesive member without using solder is also known. For example, the following patent documents 3 to 5 disclose a joining method using a conductive paste, and the following patent documents 6 to 8 disclose a joining method using a conductive film.

  In addition, expensive Ag-based members are mainly used for the bus bar electrodes on the light receiving surface and the back surface of the solar battery cell, which puts pressure on the cost. Therefore, Patent Documents 9 and 10 below disclose a method for reducing the cost by partially forming bus bar electrodes on the light receiving surface.

  Furthermore, in the following Patent Document 11, a portion where the silicon (Si) portion constituting the substrate of the solar battery cell is exposed is provided on the back surface without forming the bus bar electrode, and a conductive adhesive layer is used. A method of connecting wiring members (tab wires) is disclosed. However, carrier recombination becomes prominent in the portion where the silicon portion is exposed, and the cell characteristics may deteriorate.

  As a method for suppressing carrier recombination on the back surface, Non-Patent Document 1 below discloses a PERC (Passivated Emitter and Rear Cell) structure in which a passivation layer is formed of a silicon oxide film on the back surface of a cell. As a method of joining the wiring members on the back surface in the PERC structure, in Patent Document 12 below, a passivation layer provided with a partial opening is formed on the back surface of the cell, an Al electrode is formed so as to fill the opening, A method is disclosed in which an Ag electrode for current collection is formed so as to be in contact with the Al electrode, and an Al electrode is not formed in a region where the lead frame is soldered. However, in order to make contact with all the Al electrodes, a larger number of Ag electrodes for current collection than before are required, resulting in an increase in cost. In particular, when soldering, it is essential to form an Ag electrode in a region where a lead frame is to be attached, and it is difficult to further reduce the amount of expensive Ag used. Further, as described above, there is a concern about cell damage in the soldering method.

JP 2004-204256 A JP-A-2005-050780 JP 2000-286436 A JP 2001-357897 A Japanese Patent No. 3448924 JP 2005-101519 A JP 2007-214533 A JP 2008-300403 A Japanese Patent No. 5289625 JP 2010-27778 A International Publication No. 2012/005318 Patent No. 5174903

Appl.Phys.Lett., Vol.55 (1989), P.1363-1365

  In recent years, solar cells have attracted more and more attention as a means of supplying clean and undepleted energy, and it is expected that the cost will be reduced and the solar cell characteristics will be further improved.

  An object of this invention is to provide the solar cell unit which can acquire a favorable solar cell characteristic, reducing the member used for bus-bar electrode formation, and its manufacturing method.

  A solar battery unit according to the present invention is a solar battery unit comprising a plurality of solar battery cells and a wiring member that electrically connects the solar battery cells, and is disposed on the back surface opposite to the light receiving surface. On the back side of the solar cell having the back electrode formed, the wiring member mounting region has a conductive layer and an insulating layer.

  According to the solar cell unit of the present invention, the wiring member and the conductive layer are electrically connected while reducing the area occupied by the conductive layer by having the insulating layer occupy the mounting region of the wiring member. At the same time, the wiring member and the insulating layer can be adhered. Thereby, since the member used for bus-bar electrode formation is reduced by reducing the area of a back surface bus-bar area | region compared with the past, it can connect favorably, aiming at cost reduction. Moreover, according to the solar cell unit according to the present invention, since the mounting region of the wiring member has an insulating layer (passivation layer), it is easy to suppress exposure of the solar cells, so that the conventional backside bus bar Since it is possible to suppress carrier recombination that occurs in the region and the tab wire mounting region, good solar cell characteristics can be obtained. Moreover, according to the solar cell unit which concerns on this invention, since a photovoltaic cell and a wiring member can be connected without using solder, the characteristic deterioration accompanying use of solder can also be suppressed. According to the solar cell unit of the present invention, these effects can be suitably obtained in a PERC structure or the like in which a passivation layer is formed on the back surface.

  The conductive layer preferably contains Al, Al—Si alloy, Cu, Sn, or Ag. Thereby, sufficient electroconductivity expresses and it is easy to obtain a favorable solar cell characteristic after connecting a wiring member.

  The back electrode may be made of the same material as the conductive layer. Thereby, since the back electrode and the conductive layer can be formed at a time, the process can be simplified.

  The insulating layer preferably contains silicon nitride, silicon oxide, or aluminum oxide (alumina). Thereby, it becomes easy to suppress the recombination of a carrier as a passivation layer, and it is easy to obtain a favorable solar cell characteristic.

  In the solar cell unit according to the present invention, it is preferable that the insulating layer has an opening, and the back electrode and the solar cell are in contact with each other through the opening. Thereby, it is possible to form a BSF layer by forming an alloy layer with a solar cell (for example, a silicon portion of a substrate) on the back electrode while ensuring a passivation area on the back surface, and favorable solar cell characteristics. Easy to get.

  At least a part of the back electrode may be arranged across the mounting region of the wiring member. Thereby, even if the conductive layer is formed with a small area, sufficient current collection efficiency can be obtained.

  At least a part of the conductive layer may be disposed so as to overlap the back electrode. Thereby, the conductive path of the back electrode, the conductive layer, and the wiring member can be easily obtained, and sufficient current collection efficiency can be obtained.

  In the solar cell unit according to the present invention, the bus bar electrode is not disposed on the light receiving surface, and the surface electrode is disposed between the solar battery cell and the wiring member, and the surface electrode in the mounting region of the wiring member The aspect by which the said conductive layer is arrange | positioned in the opposing position may be sufficient. Thereby, it is possible to connect the wiring members stably and with high yield while suppressing the cost required for forming the bus bar electrodes.

  The manufacturing method of the solar cell unit according to the present invention is the above-described manufacturing method of the solar cell unit, and the disposing step of arranging the adhesive member and the wiring member in this order on the mounting region of the wiring member of the solar battery cell. And a connecting step of connecting the solar cell and the wiring member by applying pressure after the arranging step.

  In the arranging step, the adhesive member is preferably in the form of a film. Thereby, it is easy to realize a stable and uniform connection state in the mounting region of the wiring member having the conductive layer and the insulating layer.

  ADVANTAGE OF THE INVENTION According to this invention, the solar cell unit which can acquire a favorable solar cell characteristic, reducing the member used for bus-bar electrode formation, and its manufacturing method can be provided.

It is a perspective view which shows the solar cell unit which concerns on one Embodiment of this invention to a schematic diagram. It is a top view which shows typically the light-receiving surface of the conventional photovoltaic cell. It is a figure which shows typically the back surface of the conventional photovoltaic cell. It is a figure which shows typically the light-receiving surface of the photovoltaic cell which concerns on 1st Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell which concerns on 1st Embodiment. It is a top view which shows typically the insulating layer pattern in the back surface of the photovoltaic cell concerning 1st Embodiment. It is a top view which shows typically the conductive layer and back surface electrode in the back surface of the photovoltaic cell concerning 1st Embodiment. It is a schematic cross section of a solar cell unit provided with the photovoltaic cell which concerns on 1st Embodiment. It is a perspective view for demonstrating 1 process of the manufacturing method of the solar cell unit which concerns on 1st Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell which concerns on 2nd Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell concerning 3rd Embodiment. It is a top view which shows typically the insulating layer pattern in the back surface of the photovoltaic cell concerning 3rd Embodiment. It is a top view which shows typically the conductive layer and back surface electrode in the back surface of the photovoltaic cell concerning 3rd Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell which concerns on 4th Embodiment. It is a top view which shows typically the insulating layer pattern in the back surface of the photovoltaic cell concerning 4th Embodiment. It is a top view which shows typically the back surface electrode in the back surface of the photovoltaic cell which concerns on 4th Embodiment. It is a top view which shows typically the conductive layer in the back surface of the photovoltaic cell which concerns on 4th Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell which concerns on 5th Embodiment. It is a figure which shows typically the back surface of the photovoltaic cell concerning 6th Embodiment. It is a figure which shows typically an example of the light-receiving surface of a photovoltaic cell.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description is omitted in some cases.

  Moreover, the numerical value range shown using "to" shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively. “A or B” only needs to include one of A and B, or may include both. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.

  FIG. 1 is a perspective view schematically showing a solar cell unit according to this embodiment. As shown in FIG. 1, the solar cell unit 100 includes a plurality of solar cells 110 and wiring members (also referred to as “wiring wires” or “tab wires”) 111 that electrically connect the solar cells 110 to each other. I have. One surface side of the solar battery cell 110 is a light receiving surface (front surface) 110 a on which a surface electrode (also referred to as “finger electrode” or “fine wire electrode”) 112 is arranged, and the other surface side of the solar battery cell 110 is a back electrode. Is a back surface (surface opposite to the light receiving surface) 110b. The front electrode 112 and the back electrode are electrically connected to the silicon portion of the substrate 113 of the solar battery cell 110. Between the adjacent solar cells 110, the surface electrode 112 on the light receiving surface 110a side of one solar cell 110 and the back electrode on the back surface 110b side of another solar cell 110 are connected by the wiring member 111. Thereby, the string in which the photovoltaic cells 110 are connected in series is formed.

  FIG. 2 is a plan view schematically showing a light receiving surface of a conventional solar battery cell, and FIG. 3 is a diagram schematically showing a back surface of the conventional solar battery cell. As shown in FIGS. 2 and 3, the solar battery cell 10 included in the conventional solar battery unit includes an antireflection film 14 and a surface electrode 12 arranged on the light receiving surface side of the substrate 13, and a back surface side of the substrate 13. It has the back electrode 15 arrange | positioned.

  The antireflection film 14 is arranged on the light receiving surface of the substrate 13 and has an opening for arranging the surface electrode 12. The opening of the antireflection film 14 and the surface electrode 12 have a plurality of elongated straight lines. The surface electrode 12 is disposed in the opening of the antireflection film 14 and is electrically connected to the substrate 13. The back electrode 15 covers the entire back surface of the substrate 13.

  On the light receiving surface side of the solar battery cell 10, a bus bar electrode 16 a having a smaller number than the surface electrode 12 and a width wider than the surface electrode 12 is arranged so as to be orthogonal to the surface electrode 12. Further, on the back surface side of the solar battery cell 10, a bus bar electrode (back surface bus bar electrode) 16 b is arranged at a position facing the bus bar electrode 16 a on the light receiving surface. A wiring member 111 (FIG. 1) is disposed on each of the bus bar electrodes 16a and 16b, and a plurality of solar cells 10 are connected and connected.

  FIG. 4 is a diagram schematically showing a light receiving surface (surface) of the solar battery cell according to the first embodiment. FIG. 5 is a diagram schematically showing the back surface of the solar battery cell according to the first embodiment. FIG. 6 is a plan view schematically showing an insulating layer pattern on the back surface of the solar battery cell according to the first embodiment. FIG. 7 is a plan view schematically showing a conductive layer and a back electrode (back electrode pattern) on the back surface of the solar battery cell according to the first embodiment. FIG. 8 is a schematic cross-sectional view of a solar battery unit including the solar battery cell according to the first embodiment.

  The solar cell 110 according to the first embodiment includes a substrate 113, an antireflection film 114 and a front electrode 112 arranged on the light receiving surface side, an insulating layer 117, a back electrode 115 and a conductive layer (on the back side). 118) (also referred to as “backside bus bar electrode”). FIG. 4 shows a wiring member mounting region R1 on which wiring members are mounted. FIG. 5 illustrates a wiring member mounting region R2 on which the wiring member is mounted.

  The substrate 113 is, for example, a semiconductor substrate. The substrate 113 is formed in a substantially square shape by at least one selected from the group consisting of Si single crystal, polycrystal, and amorphous, for example. The four corners of the substrate 113 are chamfered in an arc shape.

  The antireflection film 114 is disposed on the light receiving surface of the substrate 113 so as to cover substantially the entire light receiving surface of the substrate 113, and has an opening in which the surface electrode 112 is disposed. For example, the opening is formed in the antireflection film 114 through fire-through in the baking step after the surface electrode 112 is disposed on the antireflection film 114. By the fire-through, the surface electrode 112 comes into contact with the substrate 113. The opening has a plurality of elongated straight lines. An example of the material of the antireflection film 114 is silicon nitride.

  The surface electrode 112 is composed of a plurality of elongated linear electrodes. The surface electrode 112 is disposed in the opening of the antireflection film 114 and is electrically connected to the substrate 113. The surface electrode 112 is arranged along a direction substantially orthogonal to the string extending direction of the solar cell unit (hereinafter referred to as “string extending direction”) on substantially the entire light receiving surface of the substrate 113, and in the strings extending direction. Are arranged at predetermined intervals along. The surface electrode 112 may include, for example, Ag and may be made of Ag.

  The insulating layer 117 is disposed on the back surface of the substrate 113 so as to cover substantially the entire back surface of the substrate 113. In the insulating layer 117, a plurality of openings 117a are formed. The openings 117a are formed along a direction substantially orthogonal to the strings extending direction, and are formed at a predetermined interval along the strings extending direction.

  Examples of the material of the insulating layer 117 include silicon nitride, silicon oxide, aluminum oxide (alumina), and the like, and any of these materials may be used as a main component. An aspect may be sufficient. Since these insulating layers 117 tend to provide a passivation effect, it is possible to prevent surface recombination of carriers and improve cell characteristics. The insulating layer 117 can be formed by a CVD method, an ALD method, sputtering, vapor deposition, or the like. The insulating layer 117 having a desired pattern may be formed by covering with a resin mask or the like, etching with hydrofluoric acid, nitric acid, or a mixed aqueous solution thereof, and then removing the resin mask with an alkaline aqueous solution or the like. . Patterning using a solid laser such as a YAG laser, Yb laser, YbYAG laser, or YVO laser, a gas laser such as a semiconductor laser, or an Ar laser is also suitable. In addition, a method in which the insulating layer forming paste is formed by patterning by screen printing and then baked is also suitable. After patterning by these methods, the treated surface may be etched with pure water by etching with an acidic aqueous solution or an alkaline aqueous solution in order to remove the damaged portion of the silicon portion of the substrate. The insulating layer 117 may be formed by directly pattern-printing an insulating layer composition by ink jet printing and baking.

  As shown in FIGS. 5 and 6, the insulating layer 117 is provided with a pattern of an opening 117a where the back electrode 115 partially contacts the silicon portion of the substrate 113 so that the back electrode 115 can partially contact. , Formed on substantially the entire back surface. In addition, when the back electrode 115 is baked and formed, if a back electrode having a so-called fire-through function that contacts with the insulating layer to make contact is used, the patterning of the insulating layer becomes unnecessary, so that the insulating layer is almost entirely formed. A BSF layer can be formed by baking after forming a back electrode paste by patterning by screen printing or the like.

  The insulating layer 117 may overlap two or more types of layers in order to obtain a passivation improvement effect and stability. For example, a silicon nitride layer may be formed on the alumina layer, or a silicon nitride layer may be formed on the silicon oxide layer. Further, they may be formed on both the back surface and the light receiving surface. When an insulating layer is also formed on the light receiving surface, an antireflection film is formed on the insulating layer. When the same insulating layer is formed on the light receiving surface and the back surface, the insulating layers on the light receiving surface and the back surface may be formed simultaneously by a vapor phase method.

  The back electrode 115 is disposed on the insulating layer 117 so as to cover substantially the entire surface of the substrate 113 and the insulating layer 117. The back electrode 115 has four long portions 115a extending in the string extending direction, and a plurality of conductive layers 118 extending in a direction substantially orthogonal to the strings extending direction are disposed between the long portions 115a. Accordingly, the adjacent long portions 115 a are connected to each other through the conductive layer 118. The conductive layer 118 is disposed at a predetermined interval along the string extending direction.

  The long portion 115 a is in contact with the silicon portion of the substrate 113 by extending to the opening 117 a of the insulating layer 117. That is, the back electrode 115 and the solar battery cell 110 are in contact with each other through the opening 117a. A region between the long portions 115a corresponds to the wiring member mounting region R2. In the wiring member mounting region R2, the conductive layer 118 is in contact with the silicon portion of the substrate 113 by extending from between the long portions 115a to the silicon portion of the substrate 113. The back electrode 115 and the conductive layer 118 may be integrally formed or may be formed separately. The conductive layer 118 may be formed in a region other than the wiring member mounting region R2.

  As a material for the back electrode 115 and the conductive layer 118, a conductive material that can obtain electrical continuity is used, and examples thereof include Al, Al—Si alloy, Cu, Sn, Ag, and the like. It is also possible to adopt an embodiment made of any of these materials (for example, an embodiment made of Al). The back electrode 115 may include the same material as the conductive layer 118 or may include a different material. The back electrode 115 may be made of the same material as that of the conductive layer 118 (that is, it may be a member made of the same material as that of the conductive layer 118).

Each of the back electrode 115 and the conductive layer 118 can be formed, for example, by applying an aluminum electrode paste containing glass powder and a silver electrode paste containing glass particles by screen printing or the like. The back electrode 115 or the conductive layer 118 containing Al may be formed on the substrate (particularly the silicon portion) by simply applying and drying the paste. However, by performing a process such as baking, the opening 117a of the insulating layer 117, etc. In the method, an alloy layer may be formed with a substrate (silicon part) to form a BSF layer, and a P ⁺ layer and an Al—Si alloy layer may be formed simultaneously. When glass paste or the like is used, the insulating layer 117 may be fired through to form the partial back electrode 115 or the conductive layer 118. In this case, the insulating layer 117 is not required to be patterned. Further, the back electrode 115 or the conductive layer 118 may be formed by electrolytic plating or electroless plating. If the same material as that of the conductive layer 118 is used as the material of the back electrode 115, the formation process becomes simple.

  As each material of the back surface electrode 115 and the conductive layer 118, one type may be used independently and two or more types may be used. For example, in order to suppress the resistance, the wiring member mounting area may be Cu, Sn, Ag, or the like, and the area other than the wiring member mounting area may be Al, Al—Si alloy, or the like. When the back electrode 115 or the conductive layer 118 containing Cu is formed, plating or paste can be used. Alternatively, the back electrode 115 or the conductive layer 118 may be formed using a paste containing phosphorus, nickel, and glass in addition to Cu. By using these, the adhesiveness with the board | substrate (especially silicon part) of a photovoltaic cell is good, and a favorable ohmic contact is obtained.

  In the wiring member mounting region R2, the conductive layer 118 is mainly formed in the opening 117a of the insulating layer 117 provided with the opening 117a before the back electrode 115 is formed. After forming the electrode 115 first, at least a part of the conductive layer 118 may be formed in the wiring member mounting region R2. At least a part of the back electrode 115 may be arranged across the wiring member mounting region R2. Furthermore, a part of the back electrode may also serve as a conductive layer. Further, at least a part of the conductive layer 118 may overlap with the back electrode 115. In these cases, when the wiring member 111 is connected to the conductive layer 118, the conductive paths of the back electrode 115, the conductive layer 118, and the wiring member 111 are easily obtained.

  On the light receiving surface of the solar battery cell 110, the wiring member 111 may be connected only by the surface electrode 112 without passing through the bus bar electrode. In this case, as shown in FIG. 4, it is only necessary that at least a part of the surface electrode 112 is disposed in the wiring member mounting region R1 where the wiring member 111 is disposed. When the surface electrode 112 is disposed between the solar battery cell 110 and the wiring member 111 (the bus bar electrode mounting region, the wiring member mounting region R1) without the bus bar electrode being disposed on the light receiving surface, It is preferable that the conductive layer 118 is disposed at a position facing the surface electrode 112 in the wiring member mounting region R2. In this case, since the conductive layer 118 is a convex portion in the wiring member mounting region R2, cell damage or the like when connected can be suppressed and cell damage can be suppressed.

  The wiring member mounting region R2 includes an insulating layer 117 and a conductive layer 118 that are exposed as the outermost surface on the back surface side in a state where no adhesive member is disposed, and a partial insulating layer (a portion where the insulating layer is partially exposed). ) 117 and a partial conductive layer 118.

  On the light receiving surface side of the solar cell unit 100, one end of the wiring member 111 for connecting the solar cells 110 in series and / or in parallel is connected to the surface electrode 112 of one solar cell 110 by an adhesive member. ing. Further, on the back surface side of the solar cell unit 100, as shown in FIG. 8, the other end of the wiring member 111 has the insulating layer 117 and the conductive layer 118 in the other solar battery cell 110 on the outermost surface. It is connected to R2 by an adhesive member 119. The wiring member 111 may be in direct contact with the conductive layer 118 as shown in FIG. 8A, and connected to the conductive layer 118 via the metal particles 119a in the adhesive member 119 as shown in FIG. 8B. May be. As the adhesive member on the light receiving surface side, a member similar to the adhesive member 119 on the back surface side can be used.

  Here, as a method of connecting the conductive layer 118 on the back surface and the wiring member 111, it is conceivable to join the conductive layer 118 and the wiring member 111 with solder. However, in the case where only the conductive layer 118 is soldered and joined by soldering, the conductive layer 118 and the wiring member 111 are joined only on the partial conductive layer 118, so that the joining strength may not be sufficient. In addition, it is difficult to maintain an electrically stable connection state with respect to the conductive layer 118. Therefore, in the present embodiment, the conductive layer 118 and the insulating layer 117 on the back surface of the solar battery cell 110 and the wiring member 111 can be joined by the adhesive member 119. By using the adhesive member 119, adhesiveness is imparted between the wiring member 111 and the conductive layer 118 and between the wiring member 111 and the insulating layer 117, so that a stable and uniform connection state can be obtained.

  Examples of the material of the adhesive member 119 include epoxy resin, acrylic resin, phenoxy resin, melamine resin, polyurethane resin, polyester resin, polyethylene resin, polyimide resin, polyamide resin, phenol resin, silicon resin, and the like. Or can be used as a mixture, copolymer, or the like in which two or more types are combined. Among these, it is preferable that at least one of an epoxy resin, a phenoxy resin, a polyethylene resin, and an acrylic resin is contained in the adhesive member from the viewpoint of easily obtaining excellent connection reliability. The material of the adhesive member 119 is preferably a material different from solder.

Even if the adhesive member 119 contains metal particles (including metal oxide particles) for imparting connectivity, electrical conductivity, elasticity, heat resistance, water resistance, gas barrier properties, an appropriate refractive index, and the like. Good. For example, an adhesive member 119 including a metal particle (for example, reference numeral 119a in FIG. 8B), a wiring member 111, and the like are disposed on the solar battery cell 110, and the metal particles are bonded to the surface electrode and conductive layer. In addition, the conductivity of the connection, the strength of bonding, etc. may be improved by the anchor effect by biting into the wiring member or the like. As the metal particles, metal oxide particles, particles covered with a metal film, particles covered with a metal oxide film, and the like can be used. The material of these particles is gold, Ag, Cu, Ni, lead, tin, bismuth, solder, gold / nickel plating plastic, copper plating, nickel plating, solder plating, ZnO, ITO, SiO ₂ , titanium oxide, oxidation Examples include indium, tin oxide, tantalum oxide, aluminum oxide (alumina), and zirconium oxide. Moreover, as these metal particles, those having a particle shape such as a chestnut shape or a spherical shape are preferable from the viewpoint of excellent embedding property of the metal particles to the adherend surface during bonding. In other words, the metal particles having such a shape are highly embeddable even with complex uneven shapes on the outer surface of the surface electrode, wiring member, etc. of the solar battery cell, and follow fluctuations such as vibration and expansion after joining. Therefore, the connection reliability can be further improved. The particle size of the metal particles is preferably 1 μm to 50 μm, and more preferably 1 μm to 30 μm.

  The adhesive member 119 is produced as a film by, for example, applying a coating solution obtained by dissolving or dispersing the above-described various materials in a solvent onto a release film such as a plastic film (for example, polyethylene terephthalate film) and removing the solvent. May be. The film-like adhesive member thus obtained is superior in terms of film thickness dimensional accuracy and pressure distribution at the time of pressure bonding, as compared with the paste-like adhesive member. Further, by using a film shape, a uniform and stable connection is possible when connecting without passing through the bus bar electrode, which contributes to improvement in yield, reliability, and the like.

  Although the example of the plastic film was given as the release film in the above, an adhesive film integrated with the wiring member can be obtained by using a metal film as the release film.

  The thickness of the adhesive member 119 in the case of forming a film can be controlled by adjusting the non-volatile content in the coating solution and adjusting the gap of the applicator or lip coater. The thickness of the film-like adhesive member is preferably 5 μm to 50 μm, and more preferably 10 μm to 35 μm.

  As the adhesive member 119, a thermosetting resin composition can be used, and a film-like thermosetting resin composition can also be used. Thereby, a photovoltaic cell and a wiring member can be connected with the hardened | cured material of a thermosetting resin composition.

The wiring member 111 is preferably a wire-like metal (including a metal oxide). Examples of the metal include gold, Ag, Cu, Ni, lead, tin, bismuth, solder, ZnO, ITO, SiO ₂ , Al, titanium oxide, indium oxide, tin oxide, tantalum oxide, aluminum oxide (alumina), and zirconium oxide. Etc. The wiring member 111 may be composed of two or more types using the above metals for the core material and the covering material, respectively. Among these, since the incident light can be reflected and the incident light can be effectively contributed to power generation, the outermost surface is preferably solder, Al, Ag, or the like.

  The manufacturing method of the solar cell unit 100 configured as described above includes, for example, an arrangement step and a connection step in this order, and may further include a sealing step.

  In the arranging step, the adhesive member 119 and the wiring member 111 are arranged in this order on the wiring member mounting region R2 of the solar battery cell 110. In the connection step after the arrangement step, the conductive layer 118 of the solar battery cell 110 and the wiring member 111 are connected by applying pressure. Similarly, on the light receiving surface side, the adhesive member 119 and the wiring member 111 are arranged in this order on the surface electrode 112 to connect the surface electrode 112 and the wiring member 111.

  In the connection step, for example, the solar battery cell 110 and the wiring member 111 are sandwiched with a desired pressure, and the conductive layer 118 of the solar battery cell 110 and the wiring member 111 are connected. In the connecting step, the adhesive member 119 can be bonded to the wiring member 111 by heating, ultraviolet rays, pressure, or the like. In order to facilitate the bonding, to surely cure the resin, and to ensure the contact between the wiring member 111 and the surface electrode 112 and the conductive layer 118, it is particularly preferable to perform bonding (thermocompression bonding) by heating and pressing. preferable. In order to prevent damage to the solar battery cell 110, the connection temperature is preferably 50 ° C. to 200 ° C., more preferably 80 ° C. to 180 ° C. as the heating temperature. The pressure is preferably 0.05 MPa or more and 2.5 MPa or less, and more preferably 0.1 MPa or more and 2.0 MPa or less.

  The solar battery unit 100 including the solar battery cell 110, the adhesive member 119, and the wiring member 111 is further installed in a laminator device in a state where a sealing member such as EVA, a glass plate, and the like are laminated, and obtained through a sealing process. You can also. FIG. 9 is a perspective view for explaining one process of the manufacturing method of the solar cell unit, and schematically shows a laminated body installed in the laminator device when the solar cell unit is manufactured through the sealing process. It is a perspective view. In this laminated body, the glass plate 200, the sealing member 210, the wiring member 111, the adhesive member (not shown), the solar cell 110, the bus bar electrode (not shown), the wiring member (not shown), and the sealing from the light receiving surface side. The member 210 and the back sheet 220 are arranged in this order. Solar cell 110 is provided with a surface electrode on the light receiving surface side and a back electrode on the back surface side. The wiring member 111 is disposed at a position orthogonal to the surface electrode of the solar battery cell 110.

  Examples of the glass plate 200 include white plate tempered glass with dimples for solar cells. Examples of the sealing member 210 include an EVA sheet made of EVA. Examples of the wiring member 111 include tab wires obtained by dipping or plating solder on Cu wires. Examples of the back sheet 220 include a PET-based or tedla-PET laminated material, a metal foil-PET laminated material, and the like.

  From the viewpoint of simultaneously performing the sealing step in the connecting step, the surface electrode 112 and the wiring member 111, and the conductive layer 118 and the wiring member 111 may be joined together with the sealing member 210 only by a sealing step by lamination. . The conditions for the sealing process by laminating are usually determined by the crosslinking conditions such as EVA generally used as the sealing member 210, but generally the conditions such as holding for about 10 minutes at 150 ° C. Can be mentioned. By connecting the surface of the wiring member 111 into at least a part of the conductive layer 118 and the surface electrode 112 by thermocompression bonding or laminating, the connection state may be made more reliable.

  The configuration of the solar cell unit is not limited to the above embodiment. For example, the configuration of the back surface of the solar cell can be arbitrarily adjusted as long as the wiring member mounting region R2 includes the conductive layer and the insulating layer.

  FIG. 10 is a diagram schematically showing the back surface of the solar battery cell according to the second embodiment. The solar cell 120 according to the second embodiment has the same configuration as that of the solar cell 110 except that the arrangement of the insulating layer, the back electrode, and the conductive layer is different. The solar battery cell 120 has an insulating layer 127, a back electrode 125, and a conductive layer 128 arranged on the back side.

  The insulating layer 127 is disposed on the back surface of the substrate 113 so as to cover substantially the entire back surface of the substrate 113. An opening 127 a is formed in the insulating layer 127. The opening 127a is formed along a direction extending substantially perpendicular to the string extending direction and a plurality of first portions formed at a predetermined interval along the string extending direction, and formed along the string extending direction. And a plurality of second portions formed at a predetermined interval along a direction substantially orthogonal to the string extending direction. The first portion and the second portion of the insulating layer 127 have a lattice shape substantially orthogonal to each other in a substantially central region in a direction substantially orthogonal to the string extending direction.

  The back electrode 125 has two long portions 125a extending in the strings extending direction. The long portion 125a is arranged on both ends of the insulating layer 127 in a direction substantially orthogonal to the string extending direction so as to sandwich a region where the lattice-shaped opening 127a of the insulating layer 127 is formed. Yes.

  A grid-like conductive layer 128 having a portion extending in the string extending direction and a portion extending in a direction substantially orthogonal to the string extending direction is disposed between the long portions 125a, whereby the long portions 125a are electrically conductive. Connected through layer 128. The long portion 125 a is in contact with the silicon portion of the substrate 113 by extending to the opening 127 a of the insulating layer 127. A region between the long portions 125a corresponds to the wiring member mounting region R2. In the wiring member mounting region R2, the conductive layer 128 is in contact with the silicon portion of the substrate 113 by extending from between the long portions 125a to the silicon portion of the substrate 113.

  FIG. 11 is a diagram schematically showing the back surface of the solar battery cell according to the third embodiment. FIG. 12 is a plan view schematically showing an insulating layer pattern on the back surface of the solar battery cell according to the third embodiment. FIG. 13 is a plan view schematically showing a conductive layer and a back electrode (back electrode pattern) on the back surface of the solar battery cell according to the third embodiment.

  The solar cell 130 according to the third embodiment has the same configuration as that of the solar cell 110 except that the arrangement of the insulating layer, the back electrode, and the conductive layer is different. The solar battery cell 130 has an insulating layer 137, a back electrode 135, and a conductive layer 138 disposed on the back side.

  The insulating layer 137 is disposed on the back surface of the substrate 113 so as to cover substantially the entire back surface of the substrate 113. The insulating layer 137 includes a first portion in which a plurality of dot-shaped openings 137a are formed, and a plurality of dot-shaped second portions 137b. The second portion 137b is arranged in an array in a substantially central region in a direction substantially orthogonal to the string extending direction, and the region in which the second portion 137b is disposed is the two first portions in the insulating layer 137. 1 is sandwiched between parts. The openings 137a are formed in an array at the first portion of the insulating layer 137.

  The back electrode 135 has two long portions 135a extending in the string extending direction. The long portion 135a is disposed on both ends of the insulating layer 137 in a direction substantially orthogonal to the string extending direction so as to sandwich the region where the second portion 137b of the insulating layer 137 is disposed. .

  The conductive layer 138 is disposed between the elongated portions 135a of the back electrode 135 on the region where the second portion 137b of the insulating layer 137 is disposed. In the conductive layer 138, a plurality of openings for exposing the second portion 137b of the insulating layer 137 are formed.

  The elongated portion 135a is in contact with the silicon portion of the substrate 113 by extending to the opening 137a of the insulating layer 137. A region between the long portions 135a corresponds to the wiring member mounting region R2. In the wiring member mounting region R2, the conductive layer 138 is in contact with the silicon portion of the substrate 113 by extending from between the long portions 135a to the silicon portion of the substrate 113.

  FIG. 14 is a diagram schematically showing the back surface of the solar battery cell according to the fourth embodiment. FIG. 15 is a plan view schematically showing an insulating layer pattern on the back surface of the solar battery cell according to the fourth embodiment. FIG. 16 is a plan view schematically showing a back electrode (back electrode pattern) on the back surface of the solar battery cell according to the fourth embodiment. FIG. 17 is a plan view schematically showing a conductive layer on the back surface of the solar battery cell according to the fourth embodiment.

  The solar cell 140 according to the fourth embodiment has the same configuration as that of the solar cell 130 except that the configuration of the wiring member mounting region R2 is different. The solar battery cell 140 has an insulating layer 147, a back electrode 145, and a conductive layer 148 disposed on the back side.

  The insulating layer 147 is disposed on the back surface of the substrate 113 so as to cover substantially the entire back surface of the substrate 113. In the insulating layer 147, a plurality of dot-shaped openings 147a and a plurality of elongated linear openings 147b are formed. The opening 147b is formed in a substantially central region in a direction substantially orthogonal to the strings extending direction, along a direction substantially orthogonal to the strings extending direction, and is formed at a predetermined interval along the strings extending direction. Yes. The region where the opening 147b is formed is located between the regions where the opening 147a is formed. The openings 147a are formed in an array.

  The back electrode 145 has two long portions 145 a extending in the strings extending direction, and has the same configuration as the back electrode 135 of the solar battery cell 130.

  The conductive layer 148 has a plurality of elongated straight lines, and is disposed corresponding to the position where the opening 147b is formed in the wiring member mounting region R2. The conductive layer 148 is in contact with the silicon portion of the substrate 113 by extending from between the long portions 145 a to the silicon portion of the substrate 113.

  By the way, the linear conductive layer may have only a portion extending in the strings extending direction without having a portion extending in a direction substantially orthogonal to the strings extending direction. FIG. 18 is a diagram schematically showing the back surface of the solar battery cell according to the fifth embodiment. The solar battery cell 150 according to the fifth embodiment is different from the above solar battery cells in the configuration of the wiring member mounting region R2. The solar battery cell 150 includes an insulating layer 157, a back electrode 155, and a conductive layer 158 arranged on the back side. In the solar battery 150, a plurality of openings are formed in the insulating layer 157 so as to extend in the string extending direction in the region between the long portions 155a of the back electrode 155. In the wiring member mounting region R2, the conductive layer 158 is arranged corresponding to the position where the opening of the insulating layer 157 is formed.

  In addition, the configuration of the grid-like conductive layer can be arbitrarily adjusted. FIG. 19 is a diagram schematically showing the back surface of the solar battery cell according to the sixth embodiment. The solar battery cell 160 according to the sixth embodiment includes an insulating layer 167, a back electrode 165, and a conductive layer 168 disposed on the back surface side. In the solar cell 160, an insulating layer includes a plurality of openings extending in a direction substantially orthogonal to the strings extending direction and one opening extending in the strings extending direction in a region between the long portions 165a of the back electrode 165. In the wiring member mounting region R <b> 2, the conductive layer 168 is disposed corresponding to the formation position of the opening of the insulating layer 167.

  Furthermore, the configuration of the light receiving surface of the solar battery cell can be arbitrarily adjusted. For example, the surface electrode 112 on the light receiving surface of the solar battery cell 110 may have an electrode portion 112a extending in the string extending direction in the wiring member mounting region R1 (FIG. 20). In this case, the electrode part 112a and the wiring member 111 can be connected without disposing the bus bar electrode.

  The number of wiring member mounting regions is not limited to the above embodiment, and an arbitrary number can be provided depending on the cell design. The number of wiring member mounting areas is 2 to 4, for example. Wiring member mounting areas can be provided on the front and back surfaces of one cell.

  The width of the linear member (for example, the conductive layer 148) or the opening (for example, the opening 147b) is preferably 2 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less. The dot diameter of the dot-shaped member (for example, the second portion 137b of the insulating layer 137) or the opening (for example, the openings 137a and 147a) is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less. .

  In the solar battery unit described above, as a solar battery in which the solar battery cell and the wiring member are joined, while reducing the conventional bus bar area, it suppresses carrier recombination that has occurred in the conventional bus bar region, and is good Solar cell characteristics can be provided.

  As a method for evaluating that the solar battery cell and the wiring member are appropriately joined, for example, current-voltage (IV) curve measurement using a solar simulator can be given. The product of the short circuit current (Isc) and the open circuit voltage (Voc) obtained at this time can be evaluated by the value of the curve factor (FF) obtained by dividing the product by the maximum current value (Pmax).

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

<Production of solar cell unit>
Example 1
First, a silicon single crystal p-type semiconductor substrate (125 mm square, thickness 200 μm) was prepared, and texture structures were formed on the light receiving surface and the back surface by alkali etching. Next, treatment was performed at a temperature of 900 ° C. for 20 minutes in a mixed gas atmosphere of phosphorus oxychloride (POCl ₃ ), nitrogen, and oxygen to form n ⁺ -type diffusion layers on the light-receiving surface, the back surface, and the side surfaces. Thereafter, the side PSG layer and the n ⁺ -type diffusion layer were removed by performing side etching, and the PSG layer on the light-receiving surface and the back surface was removed using an etching solution containing hydrofluoric acid. Further, the back surface was separately etched to remove the n ⁺ -type diffusion layer on the back surface. Thereafter, an antireflection film made of silicon nitride was formed on the n ⁺ type diffusion layer on the light receiving surface by PECVD to a thickness of about 90 nm.

Next, as an insulating layer, an aluminum oxide film was formed on the back surface by an ALD method (atomic layer deposition method), and then the pattern of FIG. 6 was formed using an Nd: YAG laser. As shown in FIG. 6, the insulating layer has a line-shaped opening, and the opening is formed so that the back electrode formed in a later step is in contact with the p-type semiconductor substrate. The line-shaped opening pattern had a line width (L _a ) of 300 μm and a line interval (line center to line center) of 0.5 mm.

  Next, an aluminum electrode paste (PVG-AD-02, manufactured by PVG Solutions, Inc.) was printed on the back surface with the pattern of FIG. 7 by a screen printing method. A conductive layer was formed on the back surface simultaneously with the back electrode using such an aluminum electrode paste, and the back surface pattern of FIG. 5 provided with a wiring member mounting region having a conductive layer and an insulating layer was obtained.

  On the other hand, a silver electrode paste (PV-16A, manufactured by DuPont) was printed on the light receiving surface with the pattern shown in FIG. 4 by screen printing. The printing conditions (screen plate mesh, printing speed and printing pressure) are appropriately adjusted so that a surface electrode having an electrode pattern width of 200 μm and a line spacing of 2.0 mm is formed and the thickness after heat treatment (firing) is 20 μm. did. Further, the front surface electrode was formed so as to be opposed to the back surface conductive layer and the back surface electrode embedded in the opening of the insulating layer through the semiconductor substrate (silicon). This was heated at a temperature of 150 ° C. for 5 minutes to evaporate the liquid medium, thereby performing a drying treatment.

  Subsequently, heat treatment (firing) is performed using a tunnel furnace (single-line transport W / B tunnel furnace, manufactured by Noritake Co., Ltd.) in the atmosphere at a maximum temperature of 800 ° C. and a holding time of 10 seconds. A solar cell element on which an electrode was formed was produced.

  In the solar cell element obtained above, a conductive film (CF) is formed on the wiring member mounting region having the light receiving surface output extraction electrode (front surface electrode) and the wiring member mounting region having the back surface output extraction electrode (conductive layer). , Manufactured by Hitachi Chemical Co., Ltd., and a wiring member (solder-plated rectangular wire for solar cell, product name: SSA-TPS 0.2 × 1.5 (20), thickness 0.2 mm × width 1). Specification of Sn-Ag-Cu lead-free solder plated to a maximum thickness of 20 μm per side on a 5 mm copper wire, manufactured by Hitachi Cable Finetech Co., Ltd., and crimping device (MB-200WH, Hitachi Chemical Co., Ltd.) The wiring member was connected to the light receiving surface output extraction electrode and the back surface output extraction electrode at 180 ° C., 2 MPa, and 10 seconds.

  Then, using a glass plate (white plate tempered glass 3KWE33, manufactured by Asahi Glass Co., Ltd.), a sealing member (ethylene vinyl acetate; EVA), and a back sheet, as shown in FIG. The connected solar cell elements / sealing member / back sheet are laminated in this order, and this laminate is used as a part of the wiring member using a vacuum laminator (LM-50 × 50, manufactured by NPC Corporation). A vacuum lamination was performed at 140 ° C. for 5 minutes to expose the solar cell unit.

(Example 2)
Instead of the configuration of Example 1, in the insulating layer, a portion where the conductive layer and the back electrode are formed in a later step is formed as an opening, and the p-type semiconductor substrate is exposed from the opening (see FIG. 12). Pattern as shown) was formed. Insulating layers having dot-shaped openings were formed in the regions on both sides of the wiring member mounting region in FIG. 11, and dot-shaped insulating layers were formed in the wiring member mounting region. In the dot-shaped opening pattern, the dot diameter was 300 μm, and the dot interval (distance from the dot center to the dot center) was 0.5 mm. The dot diameter (L _a ) of the wiring member mounting region was 200 μm, and the dot interval (L _b ) was 0.4 mm (corresponding to the shape of the opening of the conductive layer). The back surface pattern of FIG. 11 was obtained in such a manner that dots were not arranged at positions facing the front surface electrode of the light receiving surface. Others were the same as in Example 1, and a solar cell unit was produced.

(Example 3)
Instead of the insulating layer of Example 1, a silicon paste layer was formed as an insulating layer by applying a glass paste using a spin coating method, and then dried at a temperature of 150 ° C. for 5 minutes, and then at a temperature of 700 ° C. for 10 minutes. A solar cell unit was produced in the same manner as in Example 1 except that the insulating layer was formed by performing heat treatment (firing) for minutes.

(Example 4)
A solar cell unit was produced in the same manner as in Example 1 except that instead of the insulating layer of Example 1, a silicon nitride layer was formed as an insulating layer using a plasma CVD apparatus.

(Example 5)
A solar cell unit was produced in the same manner as in Example 1 except that instead of the insulating layer of Example 1, an aluminum oxide layer was formed as an insulating layer and then the silicon nitride layer of Example 4 was formed.

(Example 6)
A solar cell unit was fabricated in the same manner as in Example 1 except that instead of the insulating layer of Example 1, the silicon oxide layer of Example 3 was formed as the insulating layer and then the silicon nitride of Example 4 was formed.

(Example 7)
Instead of the configuration of Example 1, after forming the insulating layer pattern of FIG. 15, the conductive layer screen printing was performed using Cu paste containing glass particles to form the pattern of FIG. 17, and the oven heated to 150 ° C. The solvent was removed by transpiration for 15 minutes. Thereafter, a back electrode having the pattern of FIG. 16 was formed using an aluminum electrode paste, and a solar cell unit was produced in the same manner as in Example 1 except that the back pattern of FIG. 14 was obtained.

(Example 8)
In place of the Cu paste of Example 7, the pattern of FIG. 17 was formed by Sn plating. Thereafter, a back electrode having the pattern of FIG. 16 was formed using an aluminum electrode paste, and a solar cell unit was produced in the same manner as in Example 1 except that the back pattern of FIG. 14 was obtained.

Example 9
A solar cell unit was produced in the same manner as in Example 7 except that the conductive layer of Example 7 was changed to a silver electrode paste (PV-505, manufactured by DuPont).

(Comparative Example 1)
On the back surface, without forming an insulating layer, using a silver electrode paste (PV-16A, manufactured by DuPont), a conductive layer along the wiring member mounting region and a back electrode (portion other than the conductive layer) are formed. (FIG. 3) On the light receiving surface, a silver electrode paste (PV-16A, manufactured by DuPont) was used to form a surface electrode having a width of 120 μm and a bus bar electrode having a width of 1.5 mm as an electrode pattern. A so-called back surface pattern of a general solar battery cell was used. Other than that was carried out similarly to Example 1, and produced the solar cell unit.

(Comparative Example 2)
In the same manner as in Example 7, except that an insulating layer was not formed on the back surface and a silver electrode paste (PV-505, manufactured by DuPont) was printed instead of Cu paste as a conductive layer by a screen printing method. A unit was made.

<Evaluation>
Evaluation of the power generation performance of the produced solar cell unit was performed using simulated sunlight (WXS-155S-10, manufactured by Wacom Denso Co., Ltd.) and a voltage-current (IV) evaluation measuring instrument (IV CURVE TRACER MP-180). And a measuring device manufactured by Eihiro Seiki Co., Ltd.). Voc (open voltage), F., which indicates power generation performance as a solar cell. F. (Form factor) and η (conversion efficiency) were obtained by measurements based on JIS-C-8913 and JIS-C-8914, respectively. The obtained measured values (Voc, FF and η) were converted into relative values with the measured value of the solar cell unit produced in Comparative Example 1 as 100.0. Each evaluation result is shown in Table 1.

10, 110, 120, 130, 140, 150, 160 ... solar cell, 12, 112 ... surface electrode, 13, 113 ... substrate, 14, 114 ... antireflection film, 15, 115, 125, 135, 145, 155 165, back electrode, 16a, 16b, bus bar electrode, 100 solar cell unit, 110a, light receiving surface, 110b, back surface, 111, wiring member, 112a, electrode portion, 115a, 125a, 135a, 145a, 155a, 165a,. Long portion, 117, 127, 137, 147, 157, 167 ... insulating layer, 117a, 127a, 137a, 147a, 147b ... opening, 118, 128, 138, 148, 158, 168 ... conductive layer, 119 ... adhesion Member, 119a ... metal particles, 137b ... part of the insulating layer, 200 ... glass plate, 210 ... sealing member, 20 ... back sheet, R1, R2 ... wiring member mounting region.

Claims (10)

A solar cell unit comprising a plurality of solar cells and a wiring member that electrically connects the solar cells,
The solar battery cell includes a back electrode, a conductive layer, and an insulating layer disposed on the back surface opposite to the light receiving surface,
The back electrode and the conductive layer are in contact with each other in a direction orthogonal to the connection direction between the solar cells,
In the back side of the front Symbol solar cell mounting region of the wiring member has the conductive layer and the insulating layer, the solar cell unit.   The solar cell unit according to claim 1, wherein the conductive layer contains Al, an Al-Si alloy, Cu, Sn, or Ag.   The solar cell unit according to claim 1 or 2, wherein the back electrode is made of the same material as the conductive layer.   The solar cell unit according to any one of claims 1 to 3, wherein the insulating layer includes silicon nitride, silicon oxide, or aluminum oxide. The insulating layer has an opening;
The solar cell unit according to any one of claims 1 to 4, wherein the back electrode and the solar cell are in contact with each other through the opening.   The solar cell unit according to any one of claims 1 to 5, wherein at least a part of the back electrode is disposed across a mounting region of the wiring member.   The solar cell unit according to any one of claims 1 to 6, wherein at least a part of the conductive layer is disposed so as to overlap the back electrode. A surface electrode is disposed between the solar cell and the wiring member without a bus bar electrode being disposed on the light receiving surface,
The solar cell unit according to any one of claims 1 to 7, wherein the conductive layer is disposed at a position facing the surface electrode in a mounting region of the wiring member. It is a manufacturing method of the solar cell unit as described in any one of Claims 1-8,
An arrangement step of arranging the adhesive member and the wiring member in this order on the mounting region of the wiring member of the solar battery cell,
The manufacturing method of a solar cell unit including the connection process which pressurizes and connects the said photovoltaic cell and the said wiring member after the said arrangement | positioning process.   The manufacturing method of the solar cell unit according to claim 9, wherein the adhesive member is in a film form in the arranging step.

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